PHY Ch.6

Two billiard balls having the same mass roll toward each other, each moving at the same speed. What is the combined momentum of the two balls?

0 kg m/s.

A piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball that is initially at rest. After the putty sticks to the ball, both move with a combined momentum of

1 unit

A 1-kg glider and a 2-kg glider both slide toward each other at 1 m/s on an air track. They collide and stick. The combined mass moves at

1/3 m/s.

Consider massive gliders that slide friction-free along a horizontal air track. Glider A has a mass of 1 kg, a speed of 1 m/s, and collides with Glider B that has a mass of 5 kg and is at rest. If they stick upon collision, their speed after collision will be

1/6 m/s

A railroad car that is initially at rest is hit by an identical railroad car traveling with a momentum of 100 units. The cars stick together and move down the railroad tracks. The combined momentum of the cars after the collision is

100 units

A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed?

3 m/s

A canon ball travelling at 10 m/s has a momentum of 50 kg m/s. What is the mass of the ball?

5 kg

A 5000-kg freight car runs into a 10,000-kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000-kg car?

6 m/s

Total momentum before a collision equals total momentum after the collision. This describes ____

Conservation of momentum

Two objects collide without permanent deformation or heat generation. This describes ____

Elastic collision

Two objects collide with permanent deformation and/or heat generation. This describes ____

Inelastic collision

Mass multiplied by velocity. This describes ____

Momentum

The conservation of momentum is most closely related to

Newton's 3rd law

Impulse equals change in momentum of the object. This describes ____

Relationship of impulse and momentum

When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, you make the time of the impact about 10 times as great as for a stiff-legged landing. In this way the average force your body experiences is

about 1/10 as great.

Which would be more damaging, driving into a very massive concrete wall with no "give," or having a head-on collision at the same speed with an identical car moving toward you with the same speed? It would be more damaging to hit

both the same.

A car traveling along the highway needs a certain amount of force exerted on it to stop it in a certain distance. More stopping force is required when the car has

A) less stopping distance. B) more momentum. C) more mass.

If all people, animals, trains and trucks all over the world began to walk or run towards the east, then the

earth would spin a bit slower.

Force acting on an object multiplied by the time duration of its acting on the object. This describes ____

impulse

A car travelling at 10 km/hr runs into a haystack and comes to a stop. This is less dangerous than if the car had driven into a concrete wall. This is because driving into the haystack results in

increased time of impact and reduced impact force

Compared to the force that brings a small car to a stop, the force required to bring a heavy truck traveling at the same speed to a stop

may be less and may be more

An athlete performs a high jump. As she lands, she bends her knees as she reaches the ground. This increases the time of impact. The result is to ___ the force that her body experiences.

reduce

The difference between impulse and impact force involves the

time the force acts.